Japanese Laid-Open Patent Publication No. 2009-190556, Japanese Laid-Open Patent Publication No. 2009-166777, and Japanese Laid-Open Patent Publication No. 2008-55979 propose prior art examples of a wiper device including a pantograph type wiper arm. Such a wiper arm includes a main arm and a sub-arm. The main arm includes a basal portion, which is coupled to and pivoted integrally with a drive shaft. The drive shaft is rotated back and forth by drive force of a wiper motor. The sub-arm includes a basal portion pivotally coupled to a driven shaft, which is located at a different position from the drive shaft. A wiper blade is pivotally coupled to distal portions of the main arm and the sub-arm by a coupling member. When the main arm is pivoted about the drive shaft, the sub-arm is pivoted about the driven shaft following. Further, in cooperation with the pivoting of the main arm, the wiper blade changes its wiping position with respect to the wiper arm of the wiper blade. Thus, the wiper blade coupled to the pantograph type wiper arm wipes a wiping surface over a wider range than a wiper blade that is coupled to a single wiper arm, which is pivoted about a drive shaft.
Further, Japanese Laid-Open Patent Publication No. 2007-62547 describes an example of a wiper device that includes a washer nozzle for ejecting washer fluid onto a wiping surface. In the wiper device described in Japanese Laid-Open Patent Publication No. 2007-62547, the washer nozzle is arranged in a coupling member coupled to distal portions of a main arm and a sub-arm. A hose is connected to the washer nozzle so as to supply washer fluid.
Japanese Laid-Open Patent Publication No. 48-27428 describes a wiper device including a main arm, which has a main arm member. A main head rotates integrally with a drive shaft. The main arm member is pivotally coupled to the main head so as to move toward and away from a wiping surface. The washer nozzle is fixed to the main arm member.
However, in the wiper device described in Japanese Laid-Open Patent Publication No. 2007-62547, the hose is arranged along the wiper arm from a distal end to a basal end of the wiper arm, and the hose is fixed to the wiper arm. Thus, the hose is long. This makes it difficult to couple the hose and increases the cost of the wiper device.
Further, when the wiper arm, which is arranged at a stop position, starts to move, it is desirable that the washer fluid be ejected toward the front of the wiper blade in the moving direction of the wiper blade as wiping starts. However, in the wiper devices described in Japanese Laid-Open Patent Publication No. 2007-62547 and Japanese Laid-Open Patent Publication No. 48-27428, the wiper arm is arranged at the rear of the wiper blade in the moving direction when wiping is started. Thus, in the wiper devices described in Japanese Laid-Open Patent Publication No. 2007-62547 and Japanese Laid-Open Patent Publication No. 48-27428, to eject the washer fluid towards the front of the wiper blade in the moving direction when the wiper blade starts wiping, the washer nozzle must be arranged to extend across the upper side of the wiper blade from the wiper arm and project toward the front of the wiper blade in the moving direction when wiping is started. This increases the amount the washer nozzle projected from the wiper arm. Thus, when a vehicle provided with such a wiper device travels, the washer nozzle may receive wind resistance or produce wind noise. In addition, the outer appearance of the wiper device would be adversely affected. Further, to avoid dry wiping of the wiping surface and thereby improve the wiping performance, the washer fluid must be ejected right near the wiper blade and at the front of the wiper blade in the moving direction when wiping is started. However, if washer fluid is ejected from a washer nozzle that projects toward the front of the wiper blade in the moving direction when wiping is started, the washer fluid would be ejected substantially orthogonal to the wiping surface over a very short distance. Thus, the washer fluid may not spread over the wiping surface. To solve this problem, the washer fluid may be ejected from multiple points using a special elongated washer nozzle including multiple ejection ports, which are arranged along the longitudinal direction of the wiper blade. However, such a washer nozzle that includes many ejection ports is complicated and expensive. This increases the cost of the wiper device.